1. Field of the Invention
The present invention relates to a liquid level indicator apparatus including a selecting means intended to indicate the level of at least two liquid bodies including a chamber having a display tube and containing an indicator liquid which chamber is arranged within the indicator apparatus, an air passage connected between the chamber and said selecting means, at least two air conduits connected between said selecting means and said at least two liquid bodies, at least two dip tubes immersed in said liquid bodies and connected each to one of said air conduits, an air displacing means arranged within said indicator apparatus and operatively connected to said air passage.
Liquid level indicator apparatus for indicating the level of a liquid arranged in a container such as e.g. to indicate the oil level in the crankcase of an internal combustion motor are known. Such apparatus are connected by the agency of a hose with a dip tube or measuring tube, respectively, which is immersed into said liquid body, whereby the indicator apparatus contains a manually operated displacing member which upon operation forces a volume of air out of the dip tube which air rises in form of bubbles to the level of the liquid. Thereafter a connection arranged between the hose and the dip tube of the indicator device is opened, such that the outer liquid pressure prevailing in the container can force the air column within said hose upwardly and this air column forces in turn an indicator liquid arranged in a display tube up to a certain height, which height rises in accordance with the rising liquid level in such container.
2. Description of the Prior Art
A liquid level indicator of the kind mentioned above is disclosed for instance in the U.S. Pat. No. 4,072,053 and is mainly intended to display the level of the oil in the crankcase of an internal combustion motor.
It is, however, often the case that a motor vehicle is provided with several oil tanks or oil containers of which the liquid level must be determined. Many motor vehicles comprise an automatic transmission, having an oil as working fluid and many motor vehicles comprise further a container for a hydraulically oil which is needed in hydraulic operated devices of the vehicle, such as for instance a hydropneumatic suspension.
Quite obviously it would be possible to use for all mentioned containers individual indicator devices of the construction mentioned above; however, several such indicator devices occupy an accordingly large space and the installation thereof is considerably more expensive than the installation of one single apparatus specifically in such case when such indicator devices are mounted additionally at a later date. The solution which would appear in the first instance as an easy solution, namely to utilize a multi-valve arrangement to selectively connect one single indicator apparatus to the hoses of all individual liquid containers, is not possible because any such device must be constructed as compactly as possible such as to allow its mounting to the armature board of the motor vehicle. Thereby the air volumes working inside such arrangements would be extremely small such that the precision of the display would suffer considerably due to the switching-in of a multi-valve arrangement. Furthermore, the relatively large dimensions of such valves forbid a practical mounting thereof into the indicator apparatus, whereby at the same time a separate mounting of such valve is not possible due to technical, economical and also aesthetical reasons.